11,000 h of chemical-looping combustion operation—Where are we and where do we want to go?

Abstract

A key for chemical-looping combustion (CLC) is the oxygen carrier. The ultimate test is obviously the actual operation, which reveals if it turns to dust, agglomerates or loses its reactivity or oxygen carrier capacity. The CLC process has been operated in 46 smaller chemical-looping combustors, for a total of more than 11,000 h. The operation involves both manufactured oxygen carriers, with 70% of the total time of operation, and less costly materials, i.e. natural ores or waste materials. Among manufactured materials, the most popular materials are based on NiO with 29% of the operational time, Fe2O3 with 16% and CuO with 13%. Among the monometallic oxides there are also Mn3O4 with 1%, and CoO with 2%. The manufactured materials also include a number of combined oxides with 11% of operation, mostly calcium manganites and other combined manganese oxides. Finally, the natural ores and waste materials include ilmenite, FeTiO3 with 13%, iron ore/waste with 9% and manganese ore with 6%. In the last years a shift towards more focus on CuO, combined oxides and natural ores has been seen.A major difficulty with the scaling-up of a novel process is in the risk. First-of-itskind large-scale projects include risks of technical mistakes and unforeseen obstacles, leading to added costs or, in the worst case, failure. One way of addressing these risks is to focus on the heart of the process and build it with maximum flexibility for future use. A concept for maximum flexibility is the Multipurpose Dual Fluidized Bed (MDFB). Another is to find a suitable existing plant, e.g. a dual fluidized-bed thermal gasifier.With present emissions the global CO2 budget associated with a maximum temperature of 2ºC may be spent in around 20-25 years, whereas the CO2 budget for 1.5ºC is may be exhausted in 10 years. Thus, the need for both CO2 neutral fuels and negative emissions will become increasingly urgent as we are nearing or transgressing the maximum amount of CO2 that can be emitted without compromising the global climate agreement in Paris saying we must keep "well below" 2ºC and aim for a maximum of 1.5ºC. Thus, biomass may turn out to be a key fuel for Carbon Capture and Storage (CCS), because CO2-free power does not necessarily need CCS, but negative emissions will definitely need Bio-CCS.

Oxygen‐Carrier Development of Calcium Manganite–Based Materials with Perovskite Structure for Chemical‐Looping Combustion of Methane

“…The oxygen‐carrier materials produced generally had high reactivities and high attrition resistances but were prone to sulfur poisoning. A current review of development of oxygen‐carrier material research was published by Lyngfelt et al…”

“…In contrast to other carbon capture technologies, such as absorption or adsorption of CO 2 or oxyfuel combustion, there is no direct energy penalty for gas separation associated with CLC. General information about chemical looping and an overview of trends and developments can be found elsewhere …”

Renewable Methanol Synthesis

“…Lyngfelt et al. reports on the operational success of the CLC technology after a total of 11 000 h of operation in 46 small scale plants all over the world since 2004. The performance of CLC technology depends on the type of fuel, type of oxygen carrier, plant design, operating conditions, etc.…”

“…The oxygen carrier is recycled, hence the term looping, in such a way to avoid nitrogen from entering the gas stream. This process was first invented in 1954 [105], with a thorough thermodynamic (exergy) analysis provided by Richter and Knoch [106], coined as CLC by Ishida et al [107], and went into operation on pilot scale in 2004 [108]. Detailed reviews of the CLC process are available in the scientific literature [104,109].…”

“…Detailed reviews of the CLC process are available in the scientific literature [104,109]. Lyngfelt [108] provides a strategic analysis how this process can be upscaled to industrial production. The energy demand for CLC technology (12-22 %) is less than that required for carbon capture and storage (CCS) [109].…”